Soil Models - CAESAR II - Help

CAESAR II Users Guide

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Русский
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CAESAR II
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CAESAR II Version
12

Only use the following procedures for estimating soil distributed stiffnesses and ultimate loads when you do not have better available data or methods suited.

The soil restraint modeling algorithms used by the software are based on the following:

  • CAESAR II Basic Model

    “Stress Analysis Methods for Underground Pipelines,” L.C. Peng, published in 1978 in Pipeline Industry. For more information, see CAESAR II Basic Model.

  • American Lifelines Alliance

    "Appendix B: Soil Spring Representation" from the Guidelines for the Design of Buried Steel Pipe by the American Lifelines Alliance (http://www.americanlifelinesalliance.org/pdf/Update061305.pdf). For more information, see American Lifelines Alliance Soil Model.

Soil supports are modeled as bi-linear springs having an initial stiffness, an ultimate load, and a yield stiffness. The yield stiffness is typically set close to zero. After the ultimate load on the soil is reached, there is no further increase in load even though the displacement may continue. The axial and transverse ultimate loads must be calculated to analyze buried pipe. Many researchers differentiate between horizontal, upward, and downward transverse loads, but when the variance in predicted soil properties and methods are considered, this differentiation is often unwarranted.

The software allows the explicit entry of these data if it is necessary to your specific project.

After the axial and lateral ultimate loads are known, the stiffness in each direction can be determined by dividing the ultimate load by the yield displacement. Researchers have found that the yield displacement is related to both the buried depth and the pipe diameter. The calculated ultimate loads and stiffnesses are on a force per unit length of pipe basis.

See also

Basic Soil Modeler Dialog Box